If you want to ensure that your calculator is going to last longer, take a soft foam filter and cut out a small portion. Place it, or stick it with double sided tape on the back of the display, or possible support weak points and close up your calculator, squishing the foam filter inside.

" WHY? " That foam piece is going to press against the board or display making as an extra support for the internal components. That is going to keep things from rattling around and is going to make up as an additional support, reducing the stress on the built in supports and making them last longer!